FoxPro/Visual FoxPro - addobject

thisform.addobject("grid1",'grid')
thisform.grid1.columncount = 2
thisform.grid1.visible = .t.
thisform.grid1.addobject('columna3','column')
thisform.grid1.columna3.header1.caption = "Agregada"
thisform.grid1.columna3.sparse = .f.
thisform.grid1.columna3.addobject("check1","CheckBox")
Tengo un problema, no me muetra el check en la columa3 y tampoco el tutilo dell header de la calumna3, me podrian decir porque

Te falta:
thisform.grid1.columna3.visible = .T.